Abstract: Background and Objective: Roselle, Hibiscus sabdariffa L. var. sabdariffa is considered one of the most important medical plants all over the world. The application of different strains of bio fertilizers can help to control parasitic nematodes and to reduce the use of chemical nitrogen fertilizers and enhance the plant growth to decrease the production cost and environmental risk. The objective of this study was to maximize bio fertilizer and urea for controlling plant-parasitic nematode infected rosella in relation to improve growth and active constituents. Methodology: Field experiments were carried out to explore the role of three bio fertilizers: Azotobacter chroococcum; Bacillus polymyxa and Pseudomonas fluorescens singly and in combination with different doses of urea (0, 30, 60, 90 and 120 kg/feddan) in the control programs of plant parasitic nematodes infected roselle plants (Hibiscus sabdariffa L.) in relation to its growth characters under field conditions during two successive seasons. The experiment included 20 treatments, singly and combined between five levels of urea and different strains of bio fertilizers. The obtained data were subjected to analysis of variance (ANOVA) one way direction with LSD 5% using CoStat Software, Version 6.4 (2008). Results: All tested treatments significantly at 5% reduced soil and root population of the plant parasitic nematodes and increased the growth, yield and chemical constituents of roselle plants compared with untreated control. The highest reduction percentages in parasitic nematode population (84.3 and 85.9%) in the two successive seasons, respectively, occurred at the application of; A. chroococcum+60 kg urea/feddan. In addition, effectiveness of this combined gave a better enhancement in plant height (218.80 and 231.44 cm), fresh weight of whole plant (1227.22 and 1264.18 g) and seed yield (676.89 and 661.06 kg/feddan), in the two successive seasons, respectively, compared with untreated control. Conclusion: Finally, it could be concluded that, the best conformity of urea plus bio-fertilizers are A. chroococcum+60 kg urea/feddan. Which descendingly effective on parasitic nematodes reduction and roselle plant growth characters.PubDate: 28 July, 2017